Nondestructive fluid transfer device

ABSTRACT

Fluid transfer device may be configured as a vacuum pump particularly suited for nondestructive transfer of fluids, including blood and blood constituents. Fluid transfer device may be used for assisting in the pumping of blood through a patient&#39;s heart for reducing the load on the patient&#39;s heart, so that sheer forces are reduced, and blood pressure on the inner walls of the heart is reduced. Pump may be used as an implanted cardiac assist device, such as an aortic assist device, a ventricular assist device, or as a complete artificial heart. Industrial applications include the pumping of fluids, including destructible fluids such as foodstuff with or without food constituents of various sizes within the foodstuff. Food and other fluids may be stored until they are dispensed. By use of a vacuum, the inventive fluid transfer device may be operated at no more than atmospheric pressure. In addition, a pre-charged pressure tank may be used dependent on the application requirements, such as in the case where fluid pressure of the pumped fluid, including the backpressure of body fluids, in the case where pressure greater than atmospheric is required to sufficiently expel pumped fluid.

This application is a continuation of U.S. application Ser. No.11/482,791, filed Jul. 10, 2006, which is a continuation ofInternational Application No. PCT/US2005/00477, filed Jan. 10, 2005,which claims priority to U.S. Provisional Application No. 60/534,685,filed Jan. 8, 2004, each of which is hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

Fluid transfer devices such as pumps are known.

Artificial heart assistance devices, such as ventricular assist devices(VADs) that draw blood from one of the ventricles of the heart and pushthe blood through the aorta are known.

Known devices have proven unsatisfactory for pumping blood and othereasily damaged fluids.

Known cardiac assist devices have many drawbacks related to theparticular requirements of pumping blood, useful life, and so forth.

FIELD OF THE INVENTION

The invention relates to fluid transfer devices. More particularly, theinvention relates to nondestructive fluid transfer devices. Even moreparticularly, the invention relates to fluid transfer devicesparticularly suited for use in medical applications, such as in thepumping of blood.

SUMMARY OF THE INVENTION

It is an object of the invention to overcome the drawbacks of knowndevices.

A further object of the invention is to provide a fluid transfer device,such as a pump, usable for pumping fluids, such as liquids and gases.

A further object of the invention is to provide a fluid transfer device,such as a pump, usable for pumping destructible fluids, such as blood.

Another object of the invention is to provide a fluid transfer devicewhich may be used internally or externally for assisting the heart.

A further object of the invention is to provide a nonshearing fluidtransfer device, such as a pump.

A further object of the invention is to provide a fluid transfer devicesuch as a pump, which may be used for pumping any destructible fluid,including viscous, semi-solid, and other fluids, including foodstuffs,such as salsa or chunky spaghetti sauce for which the user wants tomaintain the integrity of the larger chunks of food, as well ascondiments, or the dispensing of non-food product, such as soaps andshampoos, as the marketplace demands.

Yet another object of the invention is to provide a fluid transferdevice which stores products until such time as the product is to bedispensed, such as for the dispensing of food, and other products,whether or not such products are readily degraded.

A still further object of the invention is to provide a fluid transferdevice such as a pump, which inherently automatically continually cleansitself, in use.

A further object of the invention is to provide a fluid transfer deviceconfigured for pumping blood that automatically cleans itself.

A further object of the invention is to provide a medical pump which maybe controlled by conventional pacemaker controls, in the case where themedical pump is used to assist the heart.

A still further object of the invention is to provide a fluid transferdevice which may be used as a cardiac assist device, such as an aorticassist device or ventricular assist device (VAD), with or without theaddition of one or more artificial heart valves.

Yet another object of the invention is to provide a fluid pump which maybe used with an additional pump and requisite valving, power source, andcontrols to serve as an artificial heart.

Yet another object of the invention is to provide a medical device fortransferring or pumping blood that has no entrapment areas, dead zones,or quiescent points that may lead to clotting and/or shearing ofplatelets and/or red blood cells (RBCs), for example, as in knowndevices.

A still further object of the invention is to provide a fluid transferdevice, such as a pump, which avoids cross-fluid transfer orcontamination.

A still further object of the invention is to provide a pump whichprevents the evacuation of pressurized gas into the fluid being pumped.

Yet another object of the invention is to provide a pump which has afail-safe mode selected to avoid destruction of the system in which thepump operates.

Another object of the invention is to provide a cardiac assist devicewhich does not hamper heart blood flow in the case where the cardiacassist device suffers a loss of power.

Yet another object of the invention is to provide a cardiac assistdevice configured so that if a leak develops then a signal is sent tothe user and/or the operation of the cardiac assist device is altered.

Another object of the invention is to provide a cardiac assist deviceconfigured so that in the event the cardiac assist device operation isaltered or stops pumping blood (such as in the case of a power failure),less clotting of blood occurs than in known devices.

A further object of the invention is to provide a cardiac assist deviceconfigured so that sufficiently little clotting of a patient's bloodoccurs so as to enable the reduction or elimination of the patient's useof antiplatelet agents and/or anticoagulants than required by the use ofknown devices.

Another object of the invention is to provide a blood pump, such as acardiac assist device, or an artificial heart, which causes little or nodegradation of constituents of the blood being pumped.

Still another object of the invention is to provide a blood pumpingdevice, such as a cardiac assist device, which substantially completelyrefreshes the volume of pumped blood and retains sufficiently littleunpumped blood in its stopped or non-pumping state, so that there issubstantially no accumulation of blood within the blood pump; i.e.,blood which is not continually refreshed.

A further object of the invention is to provide a blood pump configuredfor minimizing the surface area of the pumping mechanism in contact withthe blood being pumped, so as to minimize the surface area on whichplatelet accumulation and clotting may occur.

Another object of the invention is to provide a blood pump, such as acardiac assist device, including a pumping element configured andselected so that a predetermined platelet accumulations occurs on asurface of the pumping device in contact with the blood being pumped,the predetermined accumulation being selected so as to prevent anundesirable excess accumulation of platelets which may lead toundesirable clotting of the blood being pumped.

A further object of the invention is to provide a blood pump whichminimizes the volume of stagnant blood remaining in the pumping elementof the pump during a non-pumping stage of a pumping cycle; i.e. a devicewhich minimizes an unpumped volume resident in the blood pumping elementof the blood pump.

Yet another object of the invention is to provide a cardiac assistdevice which requires no pacemaker.

Another object of the invention is to provide a cardiac assist deviceincluding one or more sensors capable of detecting one or both of theinflux and outflow of blood into a ventricle of a heart, and/or theincrease and decrease of the fluid pressure exerted by the blood in theheart to which it is connected; the detection by such sensor(s) beingused to operate the cardiac assist device without an auxiliary control,such as a pacemaker.

Another object of the invention is to provide a method of implanting acardiac assist device, such as an aortic or ventricular assist device,completely within a patient's torso or chest and, indeed, without thesplitting of the sternum.

A further object of the invention is to provide a method of implanting acardiac device, such as an artificial heart, completely within apatient's torso or chest.

Another object of the invention is to provide a cardiac assist deviceincluding a pumping element, such as a bladder, which includes a coatingor layer or sensor adjacent the bladder and configured and selected soas to detect a fluid leak.

Another object of the invention is to minimize gas permeation into bloodbeing pumped, as occurred in prior art gas-filled systems, the reductionof the likelihood of gas permeation being accomplished by, for example,the use of a negative pressure (e.g., the development of a vacuum) todraw in blood to be pumped, and the use of fluid at atmospheric pressureto pump out blood into the interior of the heart.

Another object of the invention is to provide a blood pump, such as acardiac assist device, which reduces infection, thanks to its beingfully implantable.

A further object of the invention is to provide a blood pump, such as acardiac assist device, which may be configured for use in smallerpatients, such as infants and preadolescents.

Another object of the invention is to provide a blood pump, such as acardiac assist device, which may have a variable pumping rate andvolume, which variable pumping rate and volume may be adjusted fromoutside the patient's body, so that, as an adult patient recovers, or asa child grows, for example, the pumping rate and volume may beincreased, thereby eliminating the need to implant a new, larger device,as had been the case in the prior art.

Another object of the invention is to provide a blood pump, such as acardiac assist device, having sufficiently low energy requirements thatit may be operated by transformer coupled charging through the patient'sskin.

A further object of the invention is to provide a blood pump, such as acardiac assist device, which requires no percutaneous transfer of fluidenergy or electrical energy in order to operate.

Yet another object of the invention is to provide a blood pump, such asa cardiac assist device, which includes a pulsatile pump, including apulsatile pump with a variable pulsing rate.

A further object of the invention is to provide a blood pump, such as acardiac assist device, in which one or both of the pumped fluid volumeand the pumped fluid pressure may be varied.

Another object of the invention is to provide a blood pump, such as acardiac assist device, which may be controlled by an implanted pacemakerinside or outside of the cardiac assist device housing and/or bypressure sensors configured for sensing blood pressure within apatient's heart, which pressure sensors may be provided inside oroutside the housing of the cardiac assist device.

Another object of the invention is to provide a blood pump, such as acardiac assist device, which includes an atmospheric pressure sensor, sothat the pressure exerted by the pump may be varied to be substantiallythe same as atmospheric pressure to account for variations inatmospheric pressure, such as when the patient moves to a higheraltitude.

Yet another object of the invention is to provide a blood pump, such asa cardiac assist device, which sufficiently minimizes stagnant bloodcontained within the pumping element of the device that no valve isrequired between the pumping element and the inside portion of thepatient's heart to which the pumping device is fluidly connected.

Yet another object of the invention is to provide a blood pump which maybe fluidly connected to one or more of the interior regions of apatient's heart, including, for example, the right ventricle, the leftventricle, the aorta, and so forth.

In summary, the invention includes an expandable expansion chamber, ahole or fluid connection provided in the expansion chamber, and a powerunit operably associated with the expansion chamber for expanding theexpansion chamber sufficiently to cause a fluid to be drawn into theexpansion chamber through the hole or fluid connection.

The invention may likewise include an expansion chamber made of anelastic material.

The expansion chamber may be configured so that it has a normallyunexpanded state; i.e. in its relaxed mode, it is in an unexpandedcondition.

The power unit for expanding the expansion chamber may include acompressor.

A pressure tank may be fluidly connected with the compressor.

A valve or valves may be fluidly connected with one or more of thecompressor, the pressure tank, and the expansion chamber for controllingthe rate at which the expansion chamber expands and contracts, such asbased on the blood flow requirements of a heart which is being assistedby the inventive device.

A control may be provided for varying the pumping rate of the pump orcompressor.

The expansion chamber may include one or more lobes or fingers that drawin liquid and are filled with liquid as the expansion chamber expands,and which evacuate or expel liquid, such as blood, as the expansionchamber contracts or returns to its unexpanded state.

The lobe(s) or finger(s) are configured for sufficiently evacuating thefluid being transferred or pumped so that the expansion chamber isautomatically continually cleaned; e.g., the fluid in all areas orregions of the expansion chamber is continually replaced and removedwith newly drawn in fluid.

Relative terms such as left, right, first, second, up, and down are forconvenience only and are not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional view of a fluid transfer device,such as a ventricular assist device, fluidly connected to the rightventricle of a heart for assisting in pumping blood through the heart;

FIG. 2 is a schematic cross sectional view of fluid transfer device,such as a ventricular assist device, fluidly connected to the leftventricle of a heart for assisting in pumping blood through the heart;

FIG. 3 is schematic cross sectional view of a further fluid transferdevice, such as a ventricular assist device, shown fluidly connected toa ventricle of a heart for assisting in pumping blood through the heart;

FIGS. 4 and 5 show the embodiment of FIG. 3, in use;

FIG. 6 is a schematic cross sectional view of another fluid transferdevice according to the invention similar to FIG. 3 shown fluidlyconnected to a ventricle of a heart for assisting in the pumping ofblood through the heart;

FIG. 7 is a schematic cross sectional view of another fluid transferdevice according to the invention shown fluidly connected to both aventricle and the aorta of a heart for assisting in the pumping of bloodthrough the heart;

FIG. 8 is a schematic cross sectional view of another fluid transferdevice according to the invention shown fluidly connected to the aortaof a heart for assisting in the pumping of blood through the heart;

FIG. 9 is a schematic cross sectional view of another fluid transferdevice according to the invention shown fluidly connected to a portionof a heart for assisting in the pumping of blood through the heart;

FIG. 10 is a partial cross sectional view of the fluid transfer deviceof FIG. 9;

FIG. 11 is a schematic cross sectional view of another fluid transferdevice according to the invention that requires no pacemaker and isshown fluidly connected to a portion of a heart for assisting in thepumping of blood through the heart; and

FIG. 12 illustrates another embodiment of a fluid transfer device, suchas an artificial heart, shown with four valves for use in complete heartreplacement.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a fluid transfer device or pump according to the invention,in use as a ventricular assist device (VAD) 10.

VAD 10 of FIG. 1 is shown in use on a heart 12 having a left ventricle14 and a right ventricle 16. VAD 10 is shown in use as a rightventricular assist device (RVAD), shown fluidly connected to the rightventricle 16 of the heart.

VAD 10 may be provided with a housing 14, which may be substantiallyrigid. Housing 14 may be made of a material selected for a compatibilitywith tissue.

The fluid connection of RVAD 10 to the heart may be made with aconnector 18 compatible with heart tissue, such connectors 18 beingknown.

A pacemaker control 24 for an RVAD may be used for controlling thetiming of the RVAD in conjunction with the beating of the heart, as willbe described further below.

An expansion chamber 30 having an expanded state 32 and an unexpandedstate or mode 36 may be provided within housing 14. In expanded state ormode 32 the expansion chamber will be substantially filled with bloodand in the unexpanded or resting state 36 the expansion chamber may besubstantially empty.

A compressor or pump 42, such as an electric vacuum pump, may beprovided for pressurizing a pressure tank 44 by pumping a fluid, such asa gas into pressure tank 44. A valve 46, which may be controlled by thepacemaker control 24 and associated control(s), such as an integratedchip 48 or other electronic controls, as will be readily understood, mayserve to regulate the flow of the fluid located in the interior 48 ofthe housing for controlling the expansion and contraction of theexpansion chamber 30.

A power source 50, such as a battery contained within housing 14, or anexternal battery or pneumatic or vacuum supply, may be used to powercompressor 42. Alternatively, an externally controlled and operatedvacuum and vent source may be used to expand and contract the chamber30.

Battery 50 may be externally recharged via a body port connection 54.

Expansion chamber 30 may have one or more lobe-shaped or finger-likeextensions. Three (3) finger-like extensions are shown. One opening 58of expansion chamber 30 may be fluidly connected with connector 18 and,thus, fluidly connected to the user's heart.

In use, compressor 42 draws in fluid, such as gas, contained in interior48 of the housing, compresses the fluid, and forces the fluid into tank44, as will be readily appreciated. In this manner, as the amount of gasin interior 68 is reduced, the pressure on the exterior of expansionchamber 30 is reduced, and expansion chamber 30 expands to its expandedcondition 32, thereby drawing blood into expansion chamber 30. At theappropriate time as dictated by the heart beat, control 24 causes bloodto be discharged from expansion chamber 30 through hole or fluidconnection 58 synchronous with the discharging of the heart chamber. Theblood is discharged by opening valve 46 fluidly connected to tank 44,thereby releasing pressurized gas from tank 44, refilling interior 48,thus raising the pressure therein, and causing expansion chamber 30 toreturn to its unexpanded state 36. The expansion chamber may beconfigured so that its natural state is unexpanded state 36, theelasticity of the material of expansion chamber assisting/causing theexpansion chamber to return to its unexpanded state 36. In this manner,the expansion chamber returns to its unexpanded state should there by anunwarranted interruption in the operation of the VAD, such as in thecase of a power failure.

Quite simply, the timing of the valve may be controlled by a knownsense/pace pacemaker. The rate may automatically adjust discharge valvefiring as needed. This may be termed a “pulsatile” type device.

The tank may be at atmospheric pressure so that there would not be apositive pressure within the user's body greater than atmospheric, inuse.

As shown, RVAD 10 may be used without an artificial valve in conjunctionwith the natural valves of the heart, and need only be connected in oneplace on the heart, as appropriate, with known connective material.Beating (pumping) in sequence with the normal rate of the heart as firedby the pacemaker that senses heart rate change varies the operation ofthe compressor and/or the valve accordingly.

FIG. 2 illustrates a left ventricular assist device (LVAD) 100controlled by a pacemaker 124, and other controls depending on theconfiguration of the like components.

FIG. 3 is schematic cross sectional view of a further fluid transferdevice 130, such as a ventricular assist device, shown fluidly connectedto a ventricle of a heart for assisting in pumping blood through theheart.

Cardiac assist device 130 is similar to the embodiment of FIGS. 1 and 2,with the addition of a further cavity 132 within housing 131. Furthercavity 132 may be used to divide the interior of housing 131 into aninner cavity 133 and an outer cavity 135. As shown and described ingreater detail with reference to FIGS. 4 and 5, wall 132 defining innercavity 133 may include one or more curved regions 138, 142, and 144.Regions 138, 142, and 144 may be disclosed and configured for receivingexpandable chamber or bladder 30 in its expanded conditions. Forexample, lobes or fingers or extensions 158, 162, and 164 may expandinto the regions defined by respective ones of portions 138, 142, and144.

In use, chamber 30 need not expand into contact with the inner wall ofchamber 132. However, 132 may be configured so as to control expansionof chamber 30, as needed, in use.

FIG. 4 shows chamber or bladder 30 in an unexpanded condition atatmospheric pressure with valve 58 in a closed position.

FIG. 5 shows chamber 30 in what may be termed a fully expanded conditionhaving fully expanded lobes 168, 172, and 174 corresponding torespective ones of unexpanded lobes 158, 162, and 164.

Appropriate controls, such as a pacemaker, dedicated control chip, andthe like may be provided as will be readily understood. For example, oneor more valves 184 may be provided for controlling the accumulation andrelease of a fluid into and from pressure tank 44 into and from theinner cavity 133 for assisting in the expansion and contraction ofchamber 30.

Quite simply, as in the previous embodiment, pump 42 may force a fluidprovided in interior 133 in between the exterior of chamber 30 and thelobed inner wall 132 for developing a pressure less than atmosphericpressure within cavity 133; i.e. for developing a vacuum therein and,thus, causing chamber 30 to expand and draw in blood from the portion ofthe heart to which the device 130 is attached, in use. Then, when thedrawn in blood is to be sent back into the heart for assisting in thepumping of blood in a patient, for example, valve 184 is open to allowrelease of fluid from pressure tank 44, to pressurize fluid exitingthrough valve 44 and fill and pressurizing cavity 133 so that, with theassistance of atmospheric pressure, the blood is forced out of expansionchamber 30 into the heart, in use. Pacemaker 124 and other appropriatecontrols will govern the expansion and contraction of chamber 30, aswill be readily understood.

FIGS. 4 and 5 show the embodiment of FIG. 3, in use.

FIG. 6 is a schematic cross sectional view of another fluid transferdevice 200 according to the invention similar to FIG. 3 shown fluidlyconnected to a ventricle of a heart for assisting in the pumping ofblood through the heart.

Cardiac assist device 200, shown in use as a ventricular assist device,is similar to the embodiments of FIGS. 3-5. Cardiac assist device 200may include recharger 134 for recharging a battery for powering device200, recharger 134 being at a location remote from housing 131.

Likewise, pacemaker 124 may be located at a location distant fromhousing 134, as shown in FIG. 6, as will be readily appreciated.

FIG. 7 is a schematic cross sectional view of another fluid transferdevice 220 according to the invention shown fluidly connected to both aventricle and the aorta of a heart for assisting in the pumping of bloodthrough the heart.

Fluid transfer device 220 may be used for patients requiring both aventricular assist device 224 and an aortic assist device 234.

Pacemaker 124 may be used to govern the operation, along withappropriate controls, as will be readily understood. Likewise, recharger134, shown in a remote location, may be used to recharge a battery usedfor powering both devices, or for recharging respective batteries foundin each one of ventricular assist device 224 and aortic assist device234.

FIG. 8 is a schematic cross sectional view of another fluid transferdevice 240 according to the invention shown fluidly connected to theaorta of a heart for assisting in the pumping of blood through theheart.

Device 240 of FIG. 8 may be used as an aortic assist device 240, asshown. Pacemaker 124 may be used for controlling operation, andrecharger 134 may be used for recharging an implanted battery housedwithin the casing of aortic assist device 240, as will be readilyunderstood. Appropriate controls may be located within the housing ofaortic assist device 240, outside the housing, and fully implanted, aspatient requirements dictate, as in the other embodiments.

FIG. 9 is a schematic cross sectional view of another fluid transferdevice 250 according to the invention shown fluidly connected to aportion of a heart for assisting in the pumping of blood through theheart.

Fluid transfer device 250 may be termed a ventricular assist device, asit is shown connected to a ventricle of a patient's heart, as in otherembodiments described herein.

Ventricular assist device 250 may include an opening or fluid connection252 having no valve. Thanks to the configuration of expandable chamberor bladder 30 and the configuration of fluid connection 252, sufficientblood which had been drawn into the interior of chamber 30 during theexpansion of chamber 30 will be exited or pushed out of the interior ofchamber 30 under the influence of the pressurized fluid in the pressuretank and the pressure exerted by atmospheric pressure so thatsubstantially no stagnant blood will remain within chamber 30. In otherwords, sufficiently little stagnant blood will remain in chamber 30 soas to lead to clotting. It is likewise contemplated that in a region253, such as the illustrated narrowing region 253 of bladder 30, thebladder or expandable chamber 30 may be configured so that in itsunexpanded condition, narrowed portion 253 completely closes andfunctions as a valve. In that manner, no additional valve need be usedin the region of fluid connection 252.

FIG. 10 is a partial cross sectional view of the fluid transfer deviceof FIG. 9.

The wall or inner housing defining inner cavity 133 may be provided withone or more throughholes or perforations 254 and 256. A plurality ofperforations 254 and 256 may be used to ensure that chamber 30 isexpanded evenly, and to reduce the likelihood that a portion of chamber30 might block a single hole, in use. In this manner, the negativepressure developed by the pump may be developed in an inner volume 258for thus developing a negative pressure within the inner volume 262defined within lobed wall 132 defining a lobed cavity and outside oflobed expandable chamber 30.

As in other embodiments of the invention, a sensor may be provided fordetermining whether or not there is a fluid leak within cavity 262; i.e.a fluid leak which might correspond to fluid leaking out of expandablechamber 30, in use. In the case of ventricular assist device 250, sensor264, may sense the presence of leaked blood. Sensor 264 may sense thepresence of blood by the use of a photosensor detecting a change inlight or color within cavity 262 in the presence of blood. Sensor 264may also include a moisture sensor or hygrometer for detecting a changein moisture content or relative humidity corresponding to the presenceof a leaked fluid. Still further, sensor 264 may include a chemicalsensor detecting the presence of a chemical or change in chemicalcomposition. Sensor 264 may likewise include an electrical sensor fordetecting a change in electrical resistance, for example. These aremerely examples and are not intended to be limiting.

In this manner, an inner wall 268 may be treated or coated with achemical for indicating the presence of a leak, such as by a change inchemical properties which may be detected by sensor 264.

FIG. 11 is a schematic cross sectional view of another fluid transferdevice according to the invention that requires no pacemaker and isshown fluidly connected to a portion of a heart for assisting in thepumping of blood through the heart.

Device 270 of FIG. 11 may be used as a ventricular assist device, asshown. Device 270 may be particularly suited for compact or fullyimplanted situations. Device 270 may include a combined compressor andpressure tank or accumulator 280. Combination compressor and pressuretank 280 may include a pump or compressor 282 in one portion and apressure tank 284 in another portion.

Controls, such as an electronic control, may be provided.

A valve 294 may fluidly connect compressor 282 pressure tank 284, andinner cavity 295, for example.

A perforated wall 132, as shown in FIG. 10, may be provided so that thedevelopment of a vacuum in cavity 295 may serve to develop a respectivevacuum in cavity 297 for expanding expandable chamber 30, along thelines described above.

To further reduce size requirements, a sensor 296, such as a pressuresensor, may be provided that is configured to substitute for the use ofa pacemaker. Pressure sensor 296 may be configured to sense an increasein the blood pressure within a patient's heart, in use, so that thanksto control 274, the overall combination of elements will serve tofunction in concert with the pumping of the heart to assist in suchpumping. Thanks to the use of an appropriate pressure sensor whichdetects changes in pressure transmitted through the fluid connectionbetween the heart and pressure sensor 296, such fluid connectionincluding the fluid (i.e. the blood) within chamber 30 and the fluidwithin cavity 297, it can be readily determined at which points in timethe control 274 should cause the compressor to evacuate cavity 295 and,hence, lower the pressure below atmospheric pressure, for drawing bloodinto chamber 30 by the expansion of chamber 30, for example. Suchpressure sensors and timing would be readily understood.

FIG. 12 illustrates another embodiment of a fluid transfer device, suchas an artificial heart, shown with four valves for use in complete heartreplacement.

Fluid transfer device 300 may be used as an artificial heart 300, asshown. Artificial heart 300 may include a housing 310 including a firstsubhousing 312 and a second subhousing 314. First and second expandablelobed chambers 316 and 318 may be provided in respective housings 312and 314.

A first fluid connection 320 may be provided for fluidly connectingchamber 316 with the exterior of cavity 312. First fluid connection 320may include respective right and left fluid connections 322 and 324,each having respective left and right fluid valves 326 and 328.

In a similar manner, lobed chamber 318 may include a fluid connection340 including left and right fluid connections 342 and 344, each suchfluid connections 342 and 344 having respective left and right valves346 and 348.

In use, fluid flow would be in respective directions represented byarrows 380, 382, 386 and 388, governed by controls 370 which dictate themanner in which respective valves 324, 326, 346, and 348 are opened andclosed. As will be readily appreciated, depending on the manner in whichartificial heart 300 is attached to a patient's veins and arteries(e.g., at which ones of fluid connections 322,324,344, and 344) theartificial heart recipient's veins and arteries are being attached, oneor more of valves 326, 328, 346, and 348 may be actively controlled bycontrol 370. One or more of the valves may be controlled by theexpansion of chambers 316 and 318, depending on the intended use.

To enhance compactness, one or more combined compressors and pressuretanks 390 may be used; or, the pump 390 may be used and associated valve394 so that interior 395 of subhousing 312 may be used as the pressuretank, as described in connection with other embodiments. It will beappreciated that the various controls may be used as in the otherembodiments.

Any of the embodiments may be monitored from outside a patient's body,in use.

Any of the embodiments may be provided with variable pumping rates andvolumes, pulsatile pumping, and other fine-tuning of the pumping ofblood, in use, in order to enhance the operation of any of theembodiments, and so that any of the embodiments may be used for childrenso that the rate may be varied as they grow in stature, and for adultpatients, so that the heart pressure and volume and rate may beincreased as the patient convalesces, as deemed necessary.

It is further contemplated that any of the embodiments appropriatecoatings may be provided on any of the interior and exterior of theexpandable chambers and/or on the interior of the rigid housing or rigidlobed wall defining an outermost extent of the expansion chamber so asto eliminate platelet accumulation, reduced sheer, indicate fluid leaks,and enhance compatibility, and the like.

Any of the embodiments may be configured to minimize the surface area ofthe expandable chamber so as to minimize the surfaces on which plateletsmay accumulate, in the case where embodiments are used as cardiac assistdevices or for pumping blood.

Any of the embodiments may be configured to minimize the stagnant (i.e.unpumped) volume of the material being pumped.

A pacemaker may be eliminated in respective embodiments, depending onthe intended use.

In any of the embodiments by the use of atmospheric pressure todischarge the fluid there is a reduced likelihood that gas will permeatethe fluid being pumped, as has been the case in prior art gas-filledsystems.

It will be appreciated that devices in accordance with the invention maybe used to replace entire chambers of the heart with the use ofartificial inlet and outlet valves, as required.

It is further contemplated that two (2) of these fluid transfer devicesor pumps according to the invention, along with artificial heart valves,as required may be used to completely replace a patient's heart.

The pump may be located outside the body and used to pump blood.

In the case of children or certain conditions, the valve may bepartially open during the compression stage.

Additional control(s), such as a dedicated chip, may be provided.

One or more of the pump, compressor, pressure tank, battery, batterycharger, controls, and the like may be located inside the housing,outside the housing and inside the patient's body, and/or outside of thepatient's body, depending on patient requirements, for example, andother considerations.

While this invention has been described as having a preferred design, itis understood that it is capable of further modifications, and usesand/or adaptations of the invention and including such departures fromthe present disclosure as come within the known or customary practice inthe art to which the invention pertains, and as may be applied to thecentral features hereinbefore set forth, and as fall within the scope ofthe invention.

1. A method of pumping fluid within a patient, the method comprising:connecting an interior of an expandable lobed chamber with a source of afluid external to a housing; expanding the expandable lobed chamber intoan expanded condition by creating a negative pressure in a spaceintermediate the expandable lobed chamber and the housing; and conveyingan influx of the fluid into the expandable lobed chamber through aconnector configured to convey an outflow of the fluid from theexpandable lobed chamber.
 2. The method of claim 1, further comprising:drawing the fluid from external to the housing when the negativepressure is established.
 3. The method of claim 2, wherein drawing thefluid from external to the housing comprises drawing blood from achamber of a heart.
 4. The method of claim 1, further comprising:contracting the expandable lobed chamber into by increasing the pressureintermediate the expandable lobed chamber and the housing.
 5. The methodof claim 4, further comprising: conveying the outflow of the fluid fromthe expandable lobed chamber.
 6. The method of claim 5, whereinconveying the outflow of the fluid comprising conveying blood into achamber of a heart.
 7. The method of claim 6, further comprising:synchronizing actuation of the pump with contraction of the chamber ofthe heart.
 8. The method of claim 4, further comprising opening a valvefluidly connected to a tank to release pressurized gas from the tank. 9.The method of claim 8, further comprising filling the space intermediatethe housing and the expandable lobed chamber with the pressurized gas.10. The method of claim 5, wherein increasing the pressure intermediatethe expandable lobed chamber and the housing to approximatelyatmospheric pressure causes the expandable lobed chamber to be asubstantially empty unexpanded condition.
 11. The method of claim 1,wherein creating a negative pressure intermediate the expandable lobedchamber and the housing comprises actuating a pump located within acavity of the housing and outside the expandable lobed chamber.
 12. Themethod of claim 1, further comprising controlling the pump in responseto a heart rate.
 13. The method of claim 1, further comprising:maintaining the structural integrity of the housing when the negativepressure is established.
 14. The method of claim 1, further comprising:drawing the fluid from external to the housing when the negativepressure is established; contracting the expandable lobed chamber intoby increasing the pressure intermediate the expandable lobed chamber andthe housing; and conveying the outflow of the fluid from the expandablelobed chamber.
 15. The method of claim 14, wherein: creating a negativepressure intermediate the expandable lobed chamber and the housingcomprises actuating a pump located within a cavity of the housing andoutside the expandable lobed chamber; and increasing the pressureintermediate the expandable lobed chamber and the housing toapproximately atmospheric pressure causes the expandable lobed chamberto be an a substantially empty unexpanded condition.
 16. A method ofimplanting a cardiovascular assist device, the method comprising:providing a fluid transfer device adapted for implantation within apatient, the fluid transfer device comprising: a housing having a cavitytherein; an expandable lobed chamber provided in the cavity; a connectorfor fluidly connecting an interior of the expandable lobed chamber and asource of a fluid external to the housing, the connector being adaptedto convey both an influx of the fluid into the expandable lobed chamberand an outflow of the fluid from the expandable lobed chamber; a pumpprovided in the cavity to establish a negative pressure sufficientlygreat to cause the expandable lobed chamber to expand into an expandedcondition; the housing being configured to be fully implanted in apatient and sufficiently strong to withstand the negative pressurebetween an exterior of the lobed chamber and within the cavitysufficiently great to cause the lobed chamber to expand into theexpanded condition and draw the fluid through the connector fromexternal to the housing into the interior of the lobed chamber when thenegative pressure is established in the cavity; and the lobed chamberbeing configured so that the lobed chamber is in a substantially emptyunexpanded condition when the cavity and, hence, the lobed chamber is atatmospheric pressure; and providing instructions for implanting thefluid transfer device, including: coupling the connector to a heart ofthe patient; and actuating the pump.
 17. The method of claim 16, furthercomprising: coupling the connector to the heart of the patient.